The interaction of dimethyl ditallow ammonium chloride and sodium linear alkylbenzene sulfonate

Abstract

The interaction of a commercial sample of dimethyl ditallow ammonium chloride (Adogen| 470E) and sodium alkylbenzene sulfonate (C-550 LAS) in aqueous solution was examined. Interaction was very strong, with the ion pair association constant estimated to be 1 x 106 l/mol. At laundry use level concentrations, the mixtures were turbid. The highest turbidity was found at equimolar concentrations of C-550 LAS and Adogen| 470E. Turbidity was assumed to be due to the formation of an insoluble 1:1 complex.Both filtered and unfiltered mixtures of C-550 LAS and Adogen@ 470E were evaluated for detergency, softening and antistat performance. As the mixtures approached 1:1 stoichiometry, detergency decreased and softening and antistat performance improved. Lower detergency was explained by the loss from solution of LAS to form a 1:1 LAS-dimethyl ditallow ammonium complex. Improved softening and antistat perfromance were explained by adsorption of the insoluble complex on the cloth.Dimethyl ditallow ammonium chloride used in all measurements was also a commercial product, Adogen| 470E fabric softener concentrate. The properties of this material are given in Table 1.Concentration range of mixtures. Detergency, static decay and softening measurements were made on mixtures of C-550 LAS and Adogen| 470E over the range 10 .3 M-10 -4 M. This range corresponds to typical laundry use concentrations.Detergency. Two series of solutions were evaluated for detergency and soil deposition. In one series, C-550 LAS was mixed with Adogen@ 470E and the detergency of the mixtures was evaluated. In the second series the mixtures were first vacuum filtered through a Whatman 42 filter, and the detergency of the filtrate was then evaluated. Three mineral oil-soiled permanent press cloths and three unsoiled permanent press cloths were washed in a